1. Field of the Invention
This invention relates to new fluorine-containing polyamide-polyimide polymers and polybenzoxazole-polyimide polymers derived therefrom which exhibit improved thermal stability, improved resistance to solvents, good processability, good film-forming properties and good film characteristics.
2. Description of Related Art
Polyimides derived from aromatic diamine and dianhydride monomers are widely used in the aerospace industry and electronics industry because of their toughness, low density, thermal stability, radiation resistance, mechanical strength and good dielectric properties. However, such polyimides are often difficult to process thermally and thin films prepared therefrom are often brittle and lack acceptable optical transparency.
It has been suggested that aromatic polyimides having the hexafluoroisopropylidene linking group in the diamine and/or dianhydride monomer have improved solubility and processing properties. For example, U.S. Pat. No. 3,356,648 to Rogers discloses polyimides prepared from 2,2-bis(4-aminophenyl) hexafluoropropane; U.S. Pat. No. 4,592,925 to DuPont discloses polyimides prepared from 2,2-bis(3-aminophenyl) hexafluoropropane; U.S. Pat. No. 4,111,906 to Jones et al. discloses polyimides prepared from 2,2-bis[4-(4-aminophenoxy)phenyl] hexafluoropropane; and U.S. Pat. No. 4,477,648 to Jones et al. discloses polyimides prepared from 2,2-bis[(2-halo-4-amino-phenoxy)phenyl] hexafluoropropane. U.S. Pat. No. 4,592,925 discloses polyimides prepared by reacting 2,2-bis(3-aminophenyl) hexafluoropropane and 4,4'-hexafluoroisopropylidene-bis (phthalic anhydride), also known as 2,2-bis(3,4-dicarboxyphenyl) hexafluoropropane dianhydride.
In addition, U.S. Pat. No. 3,179,635 discloses the preparation of polyamide-polyimide polymers said to have good thermal stability and good film-forming properties which may be prepared by condensing a tetra functional aromatic dianhydride, an aromatic diamine and an aromatic acid halide. U.K. patent application GB-2188936A discloses the preparation of polyamides and polybenzoxazole derivatives thereof based on the condensation product of 2,2-bis(3-amino-4-hydroxyphenyl)-hexafluoropropane with an aromatic dicarboxylic acid or acid halide, followed by cyclization of the polyamide to form a polybenzoxazole.
In applicant's co-pending application Ser. No. 076,098, filed in the United States Patent and Trademark Office on July 21, 1987, is disclosed hydroxy polyimide polymers which, in the preferred embodiment, are prepared by forming the polymeric condensation product of hexafluoro-2,2-bis(3-amino-4-hydroxyphenyl) propane and 2,2-bis(3,4-dicarboxyphenyl) hexafluoropropane dianhydride. These polymers are particularly useful in the preparation of photoresist compositions.
Whereas the above-referred to polyimides, polyamide-polyimide and polybenzoxazole polymers are useful for the utilities disclosed, it is desirable to provide polyamide-polyimide polymers and polybenzoxazole polymers which provide not only superior thermal and thermooxidative stability, but also excellent thermal processibility, excellent resistance to solvents, low moisture uptake, low dielectric constant and good film-forming properties and film characteristics.